Apparatuses and methods consistent with exemplary embodiments relate to a superconducting rotating machine and a cooling method thereof, and more particularly, to a superconducting rotating machine in which a coolant for cooling a rotor having a superconductive coil is enabled to circulate naturally and compulsively, and a cooling method thereof.
A superconducting rotating machine includes a superconductive coil which must be cooled during the operation of the superconducting rotating machine. A metallic oxide superconductive material having the transition temperature higher than 77K is generally known in the art. A machine including a superconductive coil containing such a material may be cooled, for example, by liquid nitrogen.
A technique of cooling a rotor of a superconducting rotating machine is known in the related art.
The rotor includes a thermal conductive rotor body, and a superconductive coil made of a superconductive material and installed to a coil supporter.
The rotor body has a central cavity extending in an axial direction and having a cylindrical shape, in which coolant line members drawn out from the coil supporter are connected to a side surface of the central cavity. The line members extends to a condenser chamber of a cooling apparatus geodetically located at a higher position, so that the line members form a closed single-tube line system together with the condenser chamber and the central cavity.
The coolant is circulated in the line system due to the thermosiphon effect. The coolant condensed in the condenser chamber flows into the central cavity through the coolant line members. The coolant in the central cavity is thermally coupled to the superconductive coil as well as the coil supporter, so that the coolant is evaporated by absorbing heat. Then, the evaporated coolant fluid again arrives at the condenser chamber through the same line members, and then, the coolant is again condensed in the condenser chamber.
When cooling is performed by the thermosiphon effect, since the conveyance of the liquid coolant is enabled under the gravity, the cooling apparatus or the condenser chamber must be placed at a position higher than that of the coil supporter.
In addition, when the cooling is performed by the thermosiphon effect, since the rotor is cooled using a natural circulation of the coolant, the initial cooling time is too long.